User guide

The change in the frequency is not indicated in the output NMR spectra, and the modified frequency value remains set
even after you exit ChemDraw. Hence it is advised to set the frequency back to 300 MHz to avoid confusion in sub-
sequent NMR predictions.
Assigning structures to spectra
ChemBioDraw Ultra lets you assign structures to spectra. You can then display the structure associated with a spe-
cific peak by placing the pointer on that peak.
1. Open a spectral file.
2. Draw the structure (or structures) to assign to the spectrum.
3. Select specific atoms and bonds in the structure.
4. SHIFT-click the peak or peaks to which you want the structure assigned.
The selection rectangle surrounds the selected objects.
5. Go to Structure>Make Spectrum-Structure Assignment.
The selected atoms and bonds in the structure are associated with the selected spectral peaks.
Viewing spectral assignments
1. Click the Lasso or Marquee tool.
2. Place the pointer over a peak. The assigned atoms or bonds are highlighted.
Removing spectral assignments
To remove spectrum to structure assignments:
1. Click the Lasso or Marquee tool.
2. Select the objects from which to remove the assignment.
3. Go to Structure>Clear Spectrum-Structure.
Custom shift correction data
You can add your own shift correction data for proton prediction to supplement the existing data that the ChemNMR
algorithm uses. You provide your data in an SDfile and then use the file to update the ChemBioDraw ChemNMR data-
base.
Using a third-party tool, such as ACD Labs software or Mnova Lite, you can enhance your prediction results, thereby
supporting your analysis process. With Mnova Lite, you can assign your spectra in Mnova NMR and save those
assignments to an SD file. Add them to ChemNMR database. With enough added data, the prediction results
improve. (Consult your application’s user manual for instructions).
NMR data format
The correction data that you add to your SDF file must be in this format:
> <SHIFT>
<atom_id>,<shift_value>,<ignored>
For example:
ChemBioDraw 13.0
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